MOSCOW/KIEV, March 26 (Reuters) - Russia accused Ukraine on Wednesday of putting lives at risk by preventing Russian pilots and crew disembarking from passenger flights but the Ukrainian authorities said the report distorted the facts.

Citing information from Russian carrier Aeroflot, the Foreign Ministry said Ukrainian border officials were denying entry to Russian crews landing in Ukraine in violation of safety regulations allowing for rest periods after flights.

"Russia insists on an unconditional cessation of these irresponsible practices by Ukraine which endanger the safety of civil aviation flights," the ministry said in a statement.

Tension is high between Moscow and Kiev following Russia's annexation of Ukraine's Crimea region last week and the overthrow of Ukraine's Moscow-backed president last month.

Ukraine's border control service said the ministry's account of events did "not fully correspond with the facts."

It said it had followed orders from law enforcement agencies to stop one Russian from entering the country, not the entire crew, although the man turned out to be a pilot. When he was denied entry, the whole crew decided to return to the plane.

"No one refused the crew entry but the crew members decided themselves not to cross the border," said Oksana Ozhigova, a spokeswoman for Kiev's Borispol airport.

The border control service said it had also denied entry to two Russian crew members on two other occasions this month in the eastern Ukrainian cities of Donetsk and Kharkiv because they were on a list of people barred from entering the country.

Another Russian airline, Transaero, said it had not experienced such problems.

(Reporting by Natalia Zinets in Kiev and Alissa de Carbonnel and Gleb Stolyarov in Moscow, Editing by Timothy Heritage)